The Crime Scene

“Oh, how simple it would have been had I been here before they came like a herd of

buffalo and wallowed all over it.”A. Conan Doyle, The Boscombe Valley

Mystery

Preserving the crime scenePreserving the crime scene

First officer on the First officer on the scenescene

1.1. Determines nature of Determines nature of crimecrime

2.2. Gets medical Gets medical assistanceassistance

3.3. Arrests as necessaryArrests as necessary

4.4. Secures crime sceneSecures crime scene– Crime scene tapeCrime scene tape– BarricadeBarricade– RopeRope– GuardsGuards– Why is this important?Why is this important?

WitnessesWitnesses Must be separatedMust be separated Why?Why? Ask the following Ask the following

questionsquestions1.1. When did the crime When did the crime

occur?occur?2.2. Who called in the Who called in the

crime?crime?3.3. Who is the victim?Who is the victim?4.4. Can the perpetrator be Can the perpetrator be

identified?identified?5.5. What did you see What did you see

happen?happen?6.6. Where were you when Where were you when

you observed the crime you observed the crime scene?scene?

Primary and Secondary Crime Primary and Secondary Crime ScenesScenes

PrimaryPrimary Where the crime Where the crime

actually occurredactually occurrede.g., bank in a bank e.g., bank in a bank

robbery robbery

SecondarySecondary Related to the Related to the

crime but not where crime but not where crime took placecrime took place

e.g., getaway car, e.g., getaway car, thief’s hideout thief’s hideout

The Primary Crime SceneThe Primary Crime Scene

IncludesIncludes Spot where the Spot where the

offense took placeoffense took place Entrance and exit Entrance and exit

(or escape) routes(or escape) routes Locations of key Locations of key

pieces of evidencepieces of evidence

Observing and Documenting the Observing and Documenting the SceneScene

NotesNotes Requires investigators Requires investigators

to be observantto be observant May get details from May get details from

people that might be people that might be overlookedoverlooked

Detail every step Detail every step investigators take investigators take in in orderorder

Includes: date and time, Includes: date and time, weather, location, weather, location, description of crime, description of crime, names of people names of people involved, etc.involved, etc.

DocumentationDocumentation

PhotographyPhotography May capture details May capture details

missedmissed Special attention to Special attention to

points of entry and points of entry and exitexit

Taken at different Taken at different anglesangles

Close-upsClose-ups Ruler for scaleRuler for scale

DocumentationDocumentation SketchesSketches

Used with photography for Used with photography for perspectiveperspective

Permanent recordPermanent record Helps to note and Helps to note and

remember detailsremember details Overall layoutOverall layout Must give Must give

date & time date & time scalescale reference pointsreference points distance measurementsdistance measurements investigatorsinvestigators victimsvictims suspectssuspects legendlegend

DocumentationDocumentation

VideoVideo Another way to Another way to

record and show record and show detailsdetails

Allows for narrationAllows for narration Begin outdoors and Begin outdoors and

move indoorsmove indoors

Evidence CollectionEvidence Collection

Searching the Searching the crime scenecrime scene SystematicSystematic May require special May require special

lighting (for body lighting (for body fluids)fluids)

Method depends onMethod depends on Size of areaSize of area ComplexityComplexity LocationLocation

Delicate EvidenceDelicate Evidence

Packaged first Packaged first (bindle)(bindle)

FingerprintsFingerprints Impressions (tool, Impressions (tool,

tire, shoe)tire, shoe) FibersFibers HairHair BloodBlood

PackagingPackaging

Separate labeled Separate labeled containerscontainers

Liquids – unbreakable, Liquids – unbreakable, airtight, sealed airtight, sealed containerscontainers

Moist – non-airtight Moist – non-airtight containerscontainers

Clothing with trace Clothing with trace evidenceevidence

Some materials need Some materials need to be frozento be frozen

Collection MethodsCollection Methods

Adhesive tapeAdhesive tape Vacuum cleanerVacuum cleaner Remove part of Remove part of

crime scene (e.g., crime scene (e.g., wall, window wall, window frame)frame)

Evidence ControlsEvidence Controls

From victim and/or From victim and/or suspectsuspect BloodBlood HairHair

From the crime From the crime scenescene FibersFibers CarpetCarpet FabricFabric Other materialsOther materials

Securing EvidenceSecuring Evidence

1.1. Allow evidence to dry if Allow evidence to dry if necessarynecessary

2.2. Place (dried) evidence Place (dried) evidence on bindle paperon bindle paper

3.3. Fold bindle and tuck in Fold bindle and tuck in top flaptop flap

4.4. Place in plastic Place in plastic evidence bagevidence bag

5.5. Label and seal with Label and seal with tapetape

6.6. Collector signs name Collector signs name across tapeacross tape

7.7. Attach chain-of-custody Attach chain-of-custody formform

Chain of CustodyChain of Custody Continuous record Continuous record

showing that evidence showing that evidence kept safekept safe

Crime scene to court Crime scene to court roomroom

To examine evidenceTo examine evidence Open bag at a place other Open bag at a place other

than where originally than where originally sealedsealed

Examine evidenceExamine evidence Put back in bag and resealPut back in bag and reseal Sign name across new Sign name across new

piece of tapepiece of tape Complete chain-of-custody Complete chain-of-custody

formform

Crime ReconstructionCrime Reconstruction

UltimatelyUltimately DocumentationDocumentation EvidenceEvidence AnalysisAnalysis

Required in order Required in order to reconstruct the to reconstruct the crimecrime

Determine possible Determine possible motivemotive

““Let the evidence Let the evidence speak”speak”

RememberRemember

Our ability to observe all Our ability to observe all of the details of our of the details of our surroundings is flawed.surroundings is flawed.

We are naturally inclined We are naturally inclined to filter out unimportant to filter out unimportant informationinformation

We are naturally inclined We are naturally inclined to interpret what we see, to interpret what we see, look for patternslook for patterns

Our memories are faultyOur memories are faulty

Examine Examine systematicallysystematically

Consciously decide to Consciously decide to observe everything; observe everything; turn off filtersturn off filters

Don’t jump to Don’t jump to conclusions. The more conclusions. The more information, the better information, the better the interpretationthe interpretation

Write everything Write everything down, photograph, down, photograph, sketch, documentsketch, document